President Obama told Russian President Vladimir Putin in a 90 minute phone call on Saturday that his country sending troops into Ukraine is a “clear violation” of that country’s sovereignty, according to the White House.

But the request appeared likely to go unheeded as the Kremlin issued a defiant-sounding statement saying Putin stressed to Obama that the situation in Ukraine poses "real threats" to the life and health of Russian citizens and compatriots who live in Ukrainian territory.

"Vladimir Putin emphasized that, in the case of a further spread in violence in eastern regions (of Ukraine) and Crimea, Russia maintains the right to protect its interests and the Russian-speaking population that lives there," the Kremlin statement said.

The leaders spoke for about 90 minutes with Obama expressing his “deep concern” over Russia’s actions in the past two days and called on Putin to de-escalate tensions by withdrawing his forces back to bases in Crimea and to refrain from any interference elsewhere in Ukraine, the White House said.

Obama also called Russia's actions a "violation of international law" and said they will lead to "greater political and economic isolation," according to the readout of the conversation from the White House Office of the Press Secretary.

The United States in the coming hours and days will talk with allies and partners in the UN Security Council and others and suspend upcoming participation in preparatory meetings for the G-8 summit in Sochi, Russia, the White House also said.

Obama also discussed the situation with French President Francois Hollande and Canadian Prime Minister Stephen Harper. According to a statement released by the White House, the leaders agreed to coordinate closely and pledged to work together on a package of support and assistance to help Ukraine.

Earlier on Saturday, Secretary of State John Kerry spoke with Ukraine's President Oleksandr Turchynov "to assure him he had the strong support of the United States and commend the new government for showing the utmost restraint in the face of the clear and present danger to the integrity of their state, and the assaults on their sovereignty."

"We also urge that the Government of Ukraine continue to make clear, as it has from throughout this crisis, its commitment to protect the rights of all Ukrainians and uphold its international obligations," a statement released Saturday evening said. Kerry also convened a call with his counterparts from around the world to coordinate on next steps.

Defense Secretary Chuck Hagel spoke by telephone with his Russian counterpart and stressed that "without a change on the ground," Russia risks further instability in the region, isolation in the international community and an escalation that would threaten European and international security," the Pentagon said.

Earlier in the day, White House officials huddled in a high-level meeting to work on a response to Russia's efforts to move military forces into neighboring Ukraine, as Capitol Hill leaders pledged support for the Ukrainians and called on Obama to order an immediate U.S. response.

The meeting came hours after Russia's parliament gave Putin the military go-ahead to protect Russian interests in neighboring Ukraine.

Among those gathered at the White House were Defense Secretary Chuck Hagel, CIA Director John Brennan, Joint Chiefs of Staff Chairman Gen. Martin Dempsey and Director of National Intelligence James Clapper.

Obama warned Russia on Friday that "there will be costs" for any military maneuvers that Russian undertook in Ukraine.

Ukraine is amid a major political unrest that started three months ago and last month resulted in the ouster of President Viktor F. Yanukovych.

On Saturday, the Senate Foreign Relations Committee called on Obama to lead an immediate international effort -- including targeted sanctions -- to halt Russian military intervention.

“The United States and our European allies should immediately bring to bear all elements of our collective economic strength to stop Russian advances in Ukraine,” said Democrats and Republicans on the committee, including Tennessee Sen. Bob Corker, the top GOP lawmaker in the group.

They said Congress will also consider targeted sanctions against Russian people and entities that “undermine the sovereignty and territorial integrity of Ukraine” and that the Russian government “felt free to intervene militarily in Ukraine” because the United States and Europe have failed to make clear there will be serious consequences.

Putin says the moves are needed to protect ethnic Russians and the personnel of a Russian military base in the strategic Crimea region.

Democratic Sen. Chris Murphy tweeted that he agrees with Obama, writing “there will be consequences for Russia if they continue offensive action in #Ukraine.”

Obama on Saturday also told Putin that if Russia has concerns about the treatment of ethnic Russian and minority populations in Ukraine, the appropriate way to address them is peacefully through direct engagement with the government of Ukraine and through the dispatch of international observers under the auspices of the United Nations Security Council or the Organization for Security and Cooperation in Europe.